Desmoplastic small round cell tumor (DSRCT) typically occurs in the abdomen but may also present at other sites. We report six cases of paratesticular DSRCT. The patients, who ranged in age from 17 to 37 (mean, 28) years, presented with a scrotal mass (five cases) or testicular pain (one case). Grossly, the tumors were white to tan and firm. Typically, they involved the paratesticular soft tissue, serosal surfaces and the epididymis near the junction with the rete testis. Microscopically, the tumors consisted of nests of mitotically active "small blue cells" with scant cytoplasm embedded in a densely fibrotic stroma. Two tumors showed focal tubule formation; one of these also formed rosettes. The tumors exhibited the typical immunophenotype of DSRCT (positivity for keratin, vimentin, desmin, and neuron-specific enolase but nonreactivity with HBA-71 and anti-S-100). Four tumors metastasized to lymph nodes (retroperitoneal, cervical, and two unspecified); pulmonary metastases occurred in one of these cases and in one patient without lymph node metastases. One of the above patients treated with chemotherapy, died of disease at 16 months. The patients with pulmonary metastases (one of whom also had lymph node metastases) were treated with aggressive chemotherapy and are alive and apparently disease-free at 2.5 and 3 years, respectively. Three of the six patients, two of whom had known metastases, were lost to follow-up. The DSRCT of the paratestis has histologic and immunohistochemical features identical to its abdominal counterpart and must be differentiated from other "small blue cell" tumors of the paratesticular region.
From the Department of Pathology and Laboratory Medicine (O.W.C., T.M.U., M.T.H.), Indiana University School of Medicine, Indianapolis, Indiana; the Department of Pathology (R.H.Y.), James Homer Wright Laboratory of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; the Department of Pathology (A.P.D.T.), Regional Hospital, Treviso, Italy; and the Department of Pathology (C.D.M.F.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Address correspondence and reprint requests to Oscar W. Cummings, M.D., Department of Pathology, University Hospital, Indiana University Medical Center, 550 N. University Blvd., Room 3465, Indianapolis, IN 46202, U.S.A.